patch uml-kill-subprocesses-on-exit.patch queued to -stable tree

patch uml-kill-subprocesses-on-exit.patch queued to -stable tree

Post by gregk » Fri, 16 Nov 2007 04:00:11


This is a note to let you know that we have just queued up the patch titled

Subject: UML - kill subprocesses on exit

to the 2.6.23-stable tree. Its filename is

uml-kill-subprocesses-on-exit.patch

A git repo of this tree can be found at
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


From XXXX@XXXXX.COM Thu Nov 1 12:54:06 2007
From: Lepton Wu < XXXX@XXXXX.COM >
Date: Thu, 1 Nov 2007 15:53:27 -0400
Subject: UML - kill subprocesses on exit
To: XXXX@XXXXX.COM
Cc: LKML < XXXX@XXXXX.COM >, uml-devel < XXXX@XXXXX.COM >, Lepton Wu < XXXX@XXXXX.COM >
Message-ID: < XXXX@XXXXX.COM >
Content-Disposition: inline

From: Lepton Wu < XXXX@XXXXX.COM >

commit a24864a1d52a97e345a6bd4862a057f98364d098

uml: definitively kill subprocesses on panic

In a stock 2.6.22.6 kernel, poweroff a user mode linux guest (2.6.22.6 running
in skas0 mode) will halt the host linux. I think the reason is the kernel
thread abort because of a bug. Then the sys_reboot in process of user mode
linux guest is not trapped by the user mode linux kernel and is executed by
host. I think it is better to make sure all of our children process to quit
when user mode linux kernel abort.

[ jdike - the kernel process needs to ignore SIGTERM, plus the waitpid/kill
loop is needed to make sure that all of our children are dead before the
kernel exits ]

Signed-off-by: Lepton Wu < XXXX@XXXXX.COM >
Signed-off-by: Jeff Dike < XXXX@XXXXX.COM >
Signed-off-by: Andrew Morton < XXXX@XXXXX.COM >
Signed-off-by: Linus Torvalds < XXXX@XXXXX.COM >
Signed-off-by: Greg Kroah-Hartman < XXXX@XXXXX.COM >

---
arch/um/os-Linux/skas/process.c | 2 +-
arch/um/os-Linux/util.c | 38 ++++++++++++++++++++++++++++++++++++++
2 files changed, 39 insertions(+), 1 deletion(-)

--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -182,7 +182,7 @@ static int userspace_tramp(void *stack)

ptrace(PTRACE_TRACEME, 0, 0, 0);

- init_new_thread_signals();
+ signal(SIGTERM, SIG_DFL);
err = set_interval(1);
if(err)
panic("userspace_tramp - setting timer failed, errno = %d\n",
--- a/arch/um/os-Linux/util.c
+++ b/arch/um/os-Linux/util.c
@@ -105,6 +105,44 @@ int setjmp_wrapper(void (*proc)(void *,

void os_dump_core(void)
{
+ int pid;
+
signal(SIGSEGV, SIG_DFL);
+
+ /*
+ * We are about to SIGTERM this entire process group to ensure that
+ * nothing is around to run after the kernel exits. The
+ * kernel wants to abort, not die through SIGTERM, so we
+ * ignore it here.
+ */
+
+ signal(SIGTERM, SIG_IGN);
+ kill(0, SIGTERM);
+ /*
+ * Most of the other processes associated with this UML are
+ * likely sTopped, so give them a SIGCONT so they see the
+ * SIGTERM.
+ */
+ kill(0, SIGCONT);
+
+ /*
+ * Now, having sent signals to everyone but us, make sure they
+ * die by ptrace. Processes can survive what's been done to
+ * them so far - the mechanism I understand is receiving a
+ * SIGSEGV and segfaulting immediately upon return. There is
+ * always a SIGSEGV pending, and (I'm guessing) signals are
+ * processed in numeric order so the SIGTERM (signal 15 vs
+ * SIGSEGV being signal 11) is never handled.
+ *
+ * Run a waitpid loop until we get some kind of error.
+ * Hopefully, it's ECHILD, but there's not a lot we can do if
+ * it's somethi
 
 
 

1. [stable] patch x86_64-fix-2.6.18-regression-ptrace_oldsetoptions-should-be-accepted.patch queued to -stable tree

2. patch remove-broken-ptrace-special-case-code-from-file-mapping.patch queued to -stable tree


I put Nick's in Fedora, so it had better work... ;)

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3. patch x86_64-fix-2.6.18-regression-ptrace_oldsetoptions-should-be-accepted.patch queued to -stable tree

4. patch net-share-correct-feature-code-between-bridging-and-bonding.patch queued to -stable tree

5. patch xen-fix-register_vcpu_info.patch queued to -stable tree

6. patch fix-sys_move_pages-when-a-null-node-list-is-passed.patch queued to -stable tree

7. patch hwmon-w83627hf-don-t-assume-bank-0.patch queued to -stable tree

8. patch net-share-correct-feature-code-between-bridging-and-bonding.patch queued to -stable tree

9. [stable] [-stable PATCH] UML - fix uptime

10. patch kvm-add-vt-x-machine-check-support.patch added to 2.6.30-stable tree

11. patch acpi-remove-locking-from-pm1x_sts-register-reads.patch added to 2.6.28-stable tree

12. patch scsi-mpt2sas-add-missing-initialization-of-scsih_cmds.patch added to 2.6.32-stable tree

13. [stable] [PATCH 07/22] [PATCH] smbus unhiding kills thermal management

14. [uml-devel] [stable] [patch 3/8] uml: quick fix syscall table [urgent]

15. [uml-devel] [PATCH] UML: Use PTRACE_KILL instead of SIGKILL to kill host-OS processes (take #2)